Stress Myocardial Perfusion Imaging

Stress Myocardial Perfusion Imaging (MPI) is a test that uses a very low dose of a radioactive agent to evaluate the heart's blood flow and function at rest and after exercise.

MPI is useful for screening high risk populations, preoperative clearance, suspected coronary artery disease, following patients with known heart disease, or in the diagnosis of chest pain or shortness of breath. An intravenous catheter is placed in your arm and a radioactive tracer is injected. After adequate circulation, imaging of your heart at rest is done. You will then be asked to under go treadmill exercise test by walking on a treadmill at a progressively inclining grade and rate of speed until your heart reaches 85% of the predicted minimum rate (MPHR) and/or until your perceived exertion is greater than your usual activity levels, or until the test shows significant abnormalities.

At this time you will receive a second radioactive tracer injection. Imaging is done again after the tracer has circulated adequately. Total test time can be up to 4 hours and it is sometimes necessary to perform this test over 2 days. The first day's testing takes about 1 1/2 hours and the second day's testing takes about 1 1/2 hours as well.